If you use a site builder like Wordpress, Weebly, or Shopify, your POWr Apps probably live inside an invisible box or frame. You'll notice that when you try to make the app extremely wide, it stops at a certain point and cannot be made any wider. This is because it is filling up the entire frame, and cannot get any larger.
However, if you're comfortable making some minor edits to your site's HTML file, you can usually adjust the size of these frames to allow a full width app. For instructions on updating your site's HTML file, click the appropriate link below.